netweavr:So they went to MIT to plant bombs and got spotted by campus police? Is that how this started?

I believe so, yes. Remember, Officer J. D. Tippit spotted Lee Harvey Oswald after the assassination and got killed. It's entirely possible, though not confirmed, that these people are related to the bombing and the MIT officer spotted them based in the photographs released by the FBI. I believe this because why would two totally unrelated people be in possessions of IEDs? It would make no sense.